Pid controlled chest freezer is possessed

[nyer]

I had a keg of kolsch on gas and a half of a case of bottles in my chest freezer lagering at 35 degrees. Everything was fine for several weeks when I noticed the pid was reading minus 2 degrees. I opened the freezer to find exploded bottles and the keg frozen solid. The pressure relief valve must have opened because there was a big frozen cap beer on top of the keg and the CO2 tank was empty. So I have the keg slowly thawing out in the freezer at 55 and I'm praying that it will still be good. However for the life of me I cannot figure out what happened and why this thing went to minus 2 degrees when it was set at 35. I reset it and it is working perfectly again.

 

[zachattack]

Are you actually using PID to control your keezer instead of an on/off controller?

 

[kristiismean]

I feel your pain. and hope it's still good. but do not have high hopes.

 

[nyer]

The one I have is just like the stc 1000 but it reads in fahrenheit. It has worked perfect for about 2 years and is working perfectly again after the deep freeze.

 

[MarkO22]

i had a similar problem but instead of freezing my heat lamp remained on and my keezer was at 100 f. for some reason the thermostat called for heat and never cycled off when it reached temp. it has only happened the one time but now i check my temps every day just in case

 

[Michigan_Wolfman]

Could be Beer Gnomes, they're malevolent little bastards. ipe:

 

[MaryB]

I have 2 of these on my 2 deep freezers, my freezer to fridge conversion(I run off solar a lot, needed efficiency!), and on my fermenting fridge

http://www.amazon.com/dp/B00EYIEDOI/?tag=skimlinks_replacement-20

built in alarm so I know if something made the PID on the freezer to fridge conversion glitch. Or if the inverter kicked off and the transfer switch didn't drop it back on grid.

 

[zachattack]

The one I have is just like the stc 1000 but it reads in fahrenheit. It has worked perfect for about 2 years and is working perfectly again after the deep freeze.

Just to be clear, those are not PID controllers. If you were trying to do proportional control on a compressor it would not last very long Sorry I can't help with your mystery!

 

[nyer]

Well, I just found it below 0 again but I caught it before the keg froze again. I'm thinking that it has to be the thermocouple. I hooked up my old school johnson dial controller, hope it still works.

 

[mattd2]

If it is showing the correct actual temp I would not suspect a fault sensor. Is the controller actively cooling the freezer (is the cool light on). If it is something has gone wrong in the programming, if it's not the relay contacts have probably stuck closed. My bet is on stuck contacts.

 

[MaryB]

I use a solid state relay on the output of all PID's. Prevents that fried relay contact issue!

 

[nyer]

The johnson controller has been working perfectly so I'm sure the freezer is fine. The keg of kolsch that froze seems a little more watery than the first keg I'm drinking now. I shook the hell out of it after it thawed and carbed it back up.